systemd-cgtop — Show top control groups by their resource usage
systemd-cgtop [OPTIONS...] 
systemd-cgtop shows the top control groups of the local Linux control group hierarchy, ordered by their CPU, memory and disk I/O load. The display is refreshed in regular intervals (by default every 1s), similar in style to top(1).
Resource usage is only accounted for control
                groups in the relevant hierarchy, i.e. CPU usage is
                only accounted for control groups in the
                cpuacct hierarchy, memory usage
                only for those in memory and disk
                I/O usage for those in
                blkio. systemd(1)
                by default places all services in their own control
                group in the cpuacct hierarchy, but
                not in memory nor
                blkio. If resource monitoring for
                these resources is required it is recommended to add
                blkio and memory
                to the DefaultControllers= setting
                in /etc/systemd/system.conf (see
                systemd.conf(5)
                for details). Alternatively, it is possible to enable
                resource accounting individually for services, by
                making use of the ControlGroup=
                option in the unit files (See
                systemd.exec(5)
                for details).
To emphasize this: unless
                blkio and memory
                are enabled for the services in question with either
                of the options suggested above no resource accounting
                will be available for system services and the data shown
                by systemd-cgtop will be
                incomplete.
The following options are understood:
-h, --helpPrints a short help text and exits.
-pOrder by control group path name.
-tOrder by number of tasks in control group (i.e. threads and processes).
-cOrder by CPU load.
-mOrder by memory usage.
-iOrder by disk I/O load.
-d, --delay=Specify refresh delay
                                in seconds (or if one of
                                ms,
                                us,
                                min is specified as
                                unit in this time
                                unit).
--depth=Maximum control group tree traversal depth. Specifies how deep systemd-cgtop shall traverse the control group hierarchies. If 0 is specified only the root group is monitored, for 1 only the first level of control groups is monitored, and so on. Defaults to 2.
systemd-cgtop is an interactive tool and may be controlled via user input using the following keys:
Shows a short help text.
Immediately refresh output.
Terminate the program.
Change ordering of control groups by path, number of tasks, CPU load, memory usage resp. IO load.
Increase, resp. decrease refresh delay.